24 Questions
What is the biggest barrier in the process of cellular communication signals being transmitted across the environment?
Cell membrane
Which mode of cell stimuli reception is observable in cancer cells and involves signals from a cell to its own receptors?
Autocrine cells
Which mode of cell stimuli reception targets cells nearby by secreting soluble molecules which are able to diffuse in?
Paracrine signals
Which mode of cell stimuli reception targets cells that are further away and travels through the bloodstream to target cells?
Endocrine signals
Which mode of cell stimuli reception delivers messages over long distances but does not broadcast widely, instead delivering quickly and specifically to individual target cells?
Neuronal/Synaptic
In which mode of cell stimuli reception do receptor and signal molecules generally reside on the surface and both need to be in close contact for the signal to pass?
Contact dependent
What are receptors in cellular communication signals?
Transmembrane proteins
What is the process whereby one type of signal is converted to another within a cell?
Signal transduction
Which type of signal molecule requires receptors on the surface of target cells?
Large, hydrophilic molecules
What type of receptor can bind more than one ligand?
Receptor tyrosine kinases
What is the main role of accessory proteins in the GTPase cycle?
Needed for the GTPase cycle to take place
Which process is necessary to prevent prolonged stimulation, damage, or cell death?
Signal termination
What pathway involves a ligand activating the receptor and initiating a cascade of phosphorylations that transmit the signal downstream?
MAPK pathway
What is the role of phosphatases in cell signaling?
Deactivating proteins
Cellular communication signals are primarily transmitted through the release of gaseous molecules.
False
Endocrine signals target cells that are nearby and can diffuse through the extracellular environment.
False
Receptors are peripheral proteins that are not directly involved in signal transduction.
False
Neuronal/synaptic mode of cell stimuli reception involves the widespread broadcast of messages to multiple target cells.
False
Autocrine cells only receive signals from other nearby cells and not from their own receptors.
False
Receptors can only be located on the cell surface and not intracellularly.
False
All ligands are large, hydrophilic molecules that cannot cross the plasma membrane.
False
Signal transduction is the process whereby one type of signal is converted to another outside of a cell.
False
Receptor tyrosine kinases (RTKs) do not contain an intracellular kinase domain.
False
Phosphorylation is an irreversible process that cannot be reversed through phosphatases.
False
Study Notes
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Receptors have intracellular regions that interact with effectors, and can be located on the cell surface or intracellularly.
-
Two types of extracellular signal molecules exist: large, hydrophilic molecules that cannot cross the plasma membrane and require receptors on the surface of target cells, and small, hydrophobic molecules that can pass through the plasma membrane and bind to intracellular receptor proteins.
-
Examples of ligands include dissolved gases, amino acids, and fatty acids.
-
Signal transduction is the process whereby one type of signal is converted to another within a cell.
-
Receptor proteins contain at least one binding site for ligands, and a ligand can either activate (agonist) or repress (antagonist) a physiological response.
-
Receptors communicate the binding of a ligand to the cell and initiate cell signaling.
-
Signal transduction involves the activation of intracellular mediators, which transmit the signal to effector enzymes that bring about changes.
-
Secondary messengers alter metabolism or affect effector enzymes that activate target proteins, altering gene transcription.
-
There are three types of receptors: ligand-gated ion channels, G protein-coupled receptors, and receptor tyrosine kinases (RTKs).
-
RTKs are transmembrane receptors with an extracellular part where ligands bind, a transmembrane domain, and an intracellular kinase domain.
-
RTKs phosphorylate tyrosine residues using ATP, adding phosphate groups to specific amino acids.
-
Phosphorylation can activate or deactivate proteins and is reversible through phosphatases.
-
RTKs can also use monomeric GTPases as molecular switches, with activated GTPases relaying signals further.
-
Accessory proteins are needed for the GTPase cycle to take place.
-
Phosphorylation and GTP binding act as molecular switches and both need to be turned off.
-
The MAPK pathway is a signaling pathway in which a ligand activates the receptor, initiating a cascade of phosphorylations that transmit the signal downstream and activate target proteins.
-
Signal termination is necessary to prevent prolonged stimulation, damage, or cell death, and can occur through endocytosis, downregulation, inactivation, or production of inhibitory proteins.
-
Some receptors can bind more than one ligand or vice versa, and each cell responds to a limited set of extracellular signals.
-
Receptors have intracellular regions that interact with effectors, and can be located on the cell surface or intracellularly.
-
Two types of extracellular signal molecules exist: large, hydrophilic molecules that cannot cross the plasma membrane and require receptors on the surface of target cells, and small, hydrophobic molecules that can pass through the plasma membrane and bind to intracellular receptor proteins.
-
Examples of ligands include dissolved gases, amino acids, and fatty acids.
-
Signal transduction is the process whereby one type of signal is converted to another within a cell.
-
Receptor proteins contain at least one binding site for ligands, and a ligand can either activate (agonist) or repress (antagonist) a physiological response.
-
Receptors communicate the binding of a ligand to the cell and initiate cell signaling.
-
Signal transduction involves the activation of intracellular mediators, which transmit the signal to effector enzymes that bring about changes.
-
Secondary messengers alter metabolism or affect effector enzymes that activate target proteins, altering gene transcription.
-
There are three types of receptors: ligand-gated ion channels, G protein-coupled receptors, and receptor tyrosine kinases (RTKs).
-
RTKs are transmembrane receptors with an extracellular part where ligands bind, a transmembrane domain, and an intracellular kinase domain.
-
RTKs phosphorylate tyrosine residues using ATP, adding phosphate groups to specific amino acids.
-
Phosphorylation can activate or deactivate proteins and is reversible through phosphatases.
-
RTKs can also use monomeric GTPases as molecular switches, with activated GTPases relaying signals further.
-
Accessory proteins are needed for the GTPase cycle to take place.
-
Phosphorylation and GTP binding act as molecular switches and both need to be turned off.
-
The MAPK pathway is a signaling pathway in which a ligand activates the receptor, initiating a cascade of phosphorylations that transmit the signal downstream and activate target proteins.
-
Signal termination is necessary to prevent prolonged stimulation, damage, or cell death, and can occur through endocytosis, downregulation, inactivation, or production of inhibitory proteins.
-
Some receptors can bind more than one ligand or vice versa, and each cell responds to a limited set of extracellular signals.
Test your knowledge about the transmission and reception of cellular signals, as well as the different modes through which cells receive stimuli. Learn about autocrine and paracrine signaling and their relevance in various cellular activities.
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